1. Field of the Invention
The present invention relates to an apparatus and method for relay between networks, and more particularly, to a network relay apparatus and method using a software module.
2. Description of the Related Art
With the recent spread of various local area networks (LANs) and wired/wireless Internet networks, a home network has been studied. The home network allows household appliances to communicate with each other so that the household appliances are operated using only a single remote control and can use digital audio/video data through the Internet.
A home network can be operated using various protocols according to the characteristics of household appliances, i.e., nodes in a network. For example, Home Audio Video interoperability (HAVi), i.e., a communication standard based on an Institute of Electrical and Electronics Engineers (IEEE)1394 digital interface standard, is used to process digital audio/video data at high speed. However, Universal Plug & Play (UPnP) is used for personal computer (PC)-based household appliances. A Home Network Control Protocol (HNCP) based on low-speed Power Line Communication (PLC) may be used for household appliances such as refrigerators, air conditioners, and washing machines that operate at relatively low speed.
A home network might be constructed using only one protocol, but it is rare that people buy all household appliances using the same protocol. Since each of various protocols has its own advantages and disadvantages, it is usual that people buy household appliances using different protocols according to the appliances' characteristics. In this situation, appliances using the same protocol can communicate with each other, but appliances using different protocols cannot directly communication with each other.
Accordingly, in order to allow appliances using different protocols to efficiently communicate with each other, a network relay apparatus such as a bridge or a router that relays communication between networks is required.
FIG. 1 illustrates an example of a home network including two different sub-networks.
The home network includes a sub-network 110 using an IEEE802.11 protocol (referred to as an IEEE802.11 network 110), a sub-network 120 using a Bluetooth protocol (referred to as a Bluetooth network 120), and a network relay apparatus 130 relaying communication between the two sub-networks 110 and 120.
The network relay apparatus 130 includes a first modem unit 132 operating for communication with the IEEE802.11 network 110 and a second modem unit 134 operating for communication with the Bluetooth network 120.
When a personal digital assistant (PDA) 112 included in the IEEE802.11 network 110 transmits data to a printer 122 included in the Bluetooth network 120, data packets are transmitted first to the first modem unit 132 included in the network relay apparatus 130. The first modem unit 132 functions as a physical (PHY) layer and a medium access control (MAC) layer in a hierarchical architecture of the network relay apparatus 130. The data packets are processed by the first modem unit 132 and then transmitted to a logical link control (LLC) layer 136.
The LLC layer 136 converts addresses included in the data packets received from the first modem unit 132 using an address mapping table for network devices included in the sub-networks 110 and 120.
Thereafter, the data is transmitted to the second modem unit 134. The second modem unit 134 also functions as the PHY layer and the MAC layer. The second modem unit 134 encapsulates the data received from the LLC layer 136 in accordance with the Bluetooth protocol and then transmits the encapsulated data to the printer 122.
There are two conventional methods of configuring a network relay apparatus. In one method, the network relay apparatus is entirely configured in hardware using modem hardware. In the other method, a MAC layer and a PHY layer are configured in hardware (i.e., modem hardware), and an LLC layer is configured in a software manner. In particular, according to the latter method, a network interface card (NIC) functioning as modem hardware is usually installed in an inexpensive PC to drive software of the network relay apparatus.
However, conventional technology is limited in configuration of a network relay apparatus and needs a large amount of cost when many various protocols need to be supported in a sub-network or when a new network protocol needs to be supported after the network relay apparatus is configured and installed.
For example, when a network relay apparatus is entirely configured in hardware, separate network relay apparatuses are needed for sub-network protocol combinations, respectively. In addition, when a sub-network using a new protocol is added to an existing home network, as many network relay apparatuses as the sub-network protocols used in the existing home network are additionally needed. If a sub-network using a new protocol is added to the home network illustrated in FIG. 1, a relay apparatus relaying between the sub-network using the new protocol and the IEEE802.11 network 110 is needed. In addition, a relay apparatus relaying between the sub-network using the new protocol and the network relay apparatus 130 is needed. Consequently, the above-described solution is complicated and has many limitations.
Meanwhile, in a method where the LLC layer is configured in a software manner, the limitations are decreased. However, keeping separate NICs for different network standards, respectively, needs more expenses than installing the modem hardware. Moreover, whenever a sub-network using a new protocol is added to an existing home network, an appropriate NIC is purchased, and software for driving the NIC is additionally installed and reset.
As described above, configuring a network relay apparatus with conventional technology needs a large amount of cost and causes inconvenience to normal users who are not skilled in the art.